Difference between Power Transformer and Distribution Transformer

Sr. No.

Power Transformer

Distribution Transformer

1

The rating of power transformer is very high (in MV As).

The rating is in KVA and small.

2

This are used at generating stations is very high voltage transmission
line and at receiving end substation i.e. at the end of high voltage
transmission line.

These are used in distribution substations.

3

These normally operate at full load 980 to 90% of their capacity).

These are continuously energised whether load is present or not. Thus
energy is lost in iron losses throughout the day but Cu losses  occur only during loading. So the iron
losses should be smaller compared to Cu losses.

4

These can be either step up or step down type.

Distribution transformer is step down transformer only.

5

These are designed to have maximum efficiency at full load or near full
load.

The distribution transformer is designed to have maximum efficiency
at a load lower than the full load (usually 50%).

6

The voltage regulation is not important in case of power
transformers, these are designed for greater leakage reactance ( to limit severity
of short circuit current on occurrence of any fault).

The voltage regulations important; hence these are designed for lower
leakage reactance.

7

The volts per turn (E_t) for power transformer =0.6 to  0.7.

The volts per turn (E_t)=0.45.

8

The flux density is taken to be 1.55 to 1.7 wb/m² with
CRGO steel.

Flux density is taken to be 1.35 wb/m².